Trolling device for reducing the effectiveness of a propeller



Nov. 24, 1959 w. M. GEwlN 2,914,019

TROLLING DEVICE FOR REDUCING THE EFFECTIVENESS oF A PROPELLER Filed Sept. 27, 1954 PTTORA/EYS United States Patent Ro'LLING DEVICE FOR REDUCING THE EFFEcTrvENEss or A PRorELLEn i William Miller Gewin, Dupo, lll. Application September 27, 1954, Serial No. 458,526 Claims. (Cl. 11S-18) The present device relates generally to the motor boat art, and more particularly to a novel trolling device for use with outboard motors, or the like.

It has been well known for a long time that two-cycle outboard motors, or the like, quickly foul the spark plugs when operated at idling speeds, such as that required for trolling purposes. Various means have been resorted to for overcoming this deficiency, one of which is generally known as a trolling device which operates to reduce the effectiveness of the propeller of the outboard motor. However, trolling devices heretofore devised have been unsatisfactory for a niunber of reasons including lack of adaptability to propellers of various effective diameters,

awkward attachment to the boat, ineffectiveness at maintaining the. boat at trolling speeds, `and the like.

ln brief, the present novel trolling device is a simple composite unit including an upper attachment plate to. the lower portion of which is adjustably and pivotally connected a water diverter plate. The water diverter plate may be quickly adjusted to the desired operative position for trolling and as quickly moved to an inoperative position so that the propeller with which the trolling device is associated may move the boat through the water at desired speeds. In one embodiment of the invention, a resilient member permits the diverter plate to move rearwardly towards the propeller. In a modification, a hinge is provided which permits a portion of the device to swing rearwardly into effective relation with the motor propeller.

Therefore, an object of the present invention is to provide a novel trolling device for outboard motors, and the like, which overcomes the disadvantages existing in devices heretofore devised.

Another object is to provide a novel trolling device for outboard motors, and the like, which positively reduces the effective speed of the boat without the requirement of closing the throttle of the motor to idling speed.

Another object is to provide a novel trolling device for outboard motors, and the like, which may be readily secured to the transom of a boat in position for cooperative use with an outboard motor, or the like, and which is adjustable for use with outboard motors of different sizes.

Another object is to provide a novel trolling device for outboard motors, or the like, which will adjust itself to operative position in relation to the propeller when in use.

Another object is to provide a novel trolling device for outboard motors, and the like, which may be quickly rendered ineffective so that the propeller of the outboard motor may drive the boat through the water at desired speeds without interference from the device.

Another object is to provide a novel `trollingfdevice for outboard motors, and the like, which incorporates protective means for negotiating an unobserved sunken log or other obstruction without damager to the device.

Another object is to provide a novel trolling device for outboard motors, and the like, which is highly effecice tive in use, yet is inexpensive and durable, which is co1- lapsible to a relatively Vsmall package for transporting purposes, and which requires minimum instruction for installation and successful use.

The foregoing and other objects and advantages are apparent from the following description taken with the accompanying drawing, in which:

Figure 1 is a rear elevational view of a trolling device for outboard motors, and the like, incorporating the teachings of the present invention, the water diverter plate being indicated in its inoperative position by dotted mes;

Figure 2 is an end elevational view thereof on an enlarged scale;

Figure 3 is an enlarged vertical cross-sectional view taken on substantially the line 3 3 ofy Figure 1;

Figure 4 is a View looking toward the center portion of the transom of a boat with the present trolling device thereonrin association with an outboard motor illustrated in dotted lines; j

Figure 5 is a side elevational view of the rear portion of the boat shown in Figure 4 with the trolling device and outboard motor illustrated in operative relation thereto, the water diverter plate being shown against the gear casing at the bottom of the propeller shaft housing;

Figure 6 is arear elevational view of a modified trolling device;

Figure 7 is an enlarged cross-sectional view on substantially the line 7-7 of Figure 6;

Figure 8 is an enlarged cross-sectional view on substantially the line 8--8 of Figure 6; and

Figure 9 is a side elevational view of the modified device attached to the transom of a boat, an outboard motor being indicated in dotted lines.

Referring to the `drawing more particularly by reference numerals, 10 indicates generally a trolling device incorporating the principles of the present invention. The trolling device 10 includes a base or attachment plate 12, a water diverter plate 14, and a lresilient pivotal connection 16 between the plates 12 and 14. Preferably, the plates 12 and 14 are of lightweight resilient material, such as spring aluminum.

lThe plate 12 is generally rectangular in form, and in one-embodiment is approximately eight inches in width and approximately fourteen inches in depth or length. At the top of the plate 12 is a mounting flange `118 for ease of mounting on top of the boat transom, and at the bottom thereof are turned-up corners 20 which cooperate with bosses or raised areas 22 to form a guide for the plate 14 during vertical adjustment, as is more particularly pointed out below. The angle of the flange 18 with the plate 12 is shown as substantially ninety degrees, but the angle may be readily changed to suit the particular installation by bending the flange 18 with a pair of pliers, or the like. The raised areas 22`also prevent pivotal movement of the diverter plate 14 relative to the plate 12 when the device 10 is in use, as is clear from Figures 4 and 5. A safety chain 23 may be connected to the flange 18 or elsewhere for attachment to the boat with which the device 10 is used.

The water diverter plate 14 is also generally rectangular in shape with a semicircular lowersend, and includes an upper flange 24 which may be grasped by the fingers of the hand in `selected movement of the plate 14. A slot 26 extends centrally longitudinally of the plate 14 to permit relative movement between the plates 12 and 14. In one embodiment of the device 10, the width of the plate 14 is approximately seven and three-eighths inches and the length or depth is approximately thirteen inches.

The resilient pivotal connection 16 maintains the plates 12 and 14 in adjustable cooperative relationship and permits movement of the latter bodily away from the former,

as is clear from the drawings. A bolt 28 is mounted in a suitable aperture in the plate 12 and extends through the slot 26 in the plate 14; A compression spring 30 surrounds the bolt V28`and"bears against a washer 32 adjacent the plate 14 andV against a cupped washer 34 abutting a nut 36 threadedly engaging the bolt 28.

It will be observed from Figure l that the bolt 28 is mounted in relation to the lower edge of the Vplate 12 so that the plate 14, when pivoted to theV inoperative position shown in dotted lines, will be disposed in'locking position above the turned-up corners 20 and against the raised areas 22 under the inuence of the spring 30.'

In Figures 4 and 5, the trolling device 10 is shown mounted on the forwardly sloping transom 38 Vof a boat 40 in operative relation With an outboard motor 42 having the usual propeller 44. As illustrated, the base or mounting plate 12 is maintained in position against the transom 38 by theusual clamps (not shown) of the outboard m'otor 42 which conventionally engage the top of the transom 38. This is the simplest way to maintain the trolling device in operative position at the rear of the boat 40. However, it is to be understood that the device 10 may be maintained in position by other means, such as independent clamps, nuts and bolts, or the like. For some installations, it may engage the outboard motor for support.

In Figures 4 and 5, the trolling device 10 is in operative relation with the propeller 44 of the outboard motor 42, that is, the water diverter plate 14 is located forwardly of the propeller 44 in position to divert forward propeller thrust to relatively ineffective balanced radial thrust. The diverter plate 14 assumes the curved position as illustrated under the force of the water. For most ecient results. the plate 14 should be adjacent the gear casing; usually, it will rest against the gear casing or the anti-cavitation plate of the motor. Hence. the outboard motor 42 mav be maintained at normal driving throttle, yet the boat 40 will be moved at the desired slow trolling speed. This insures long continuous operation of the motor and avoids the plug fouling which inevitably occurs when outboard motors are operated for relatively long periods at idling speeds. As is well known, the lubricating oil for outboard motors, and the like, is applied with the gasoline. hence, fouling of the plugs occurs quickly at low speeds.

It is obvious that the connection 16 maintains the plates 12 and 14 firmly in adjusted position, yet it is a simple matter to slide the plate 14 vertically up or down as is reouired in relation to the plate 12 simply by grasping the an'ge 24 with the fingers of the hand and pulling up or pushing down as the case may be. It is also the same simple matter to rotate the plate 14 to the position shown in dotted lines in Figure l, which is the desired position when the boat 40 is being moved about under the desired full power of the outboard motor 42. The mounting plate 12 and diverter plate 14 are both above the bottom of the boat 40 when the plate 14 is in inoperative position which prevents drag and the throwing of Water.

By reference to Figure 5. it should be noted that should the trolling device 10 strike a sunken log, or the like, when in the operative position, the resiliency of the connection 16 and of the plates 12 and 14 will permit the plate 14 to move rearwardly in pivotal manner about the upper edge thereof, thereby reducing to a minimum the likelihood of damage to the device 10. The propeller 44 is usually mounted in a manner to permit rearward move- 3'0. 'Corresponding' 'parts of the' device'tlbear the same reference 'numerals'- :applied to the' device` 101'" 'It' Willbef4 noted that the rubber washer 58 will -give sufliciently to permit the plate 14 to be pivoted into inoperative position.

The device 50 readily adapts itself for use even with boats having transoms which slope sharply forwardly, as the transom 6l! of the boat 62 in Figure 9. The hinge S6 permits the diverter plate 14 to swing rearwardly against the gear casing'of the outboard motor 42 and into close operative relation with the propeller 44, as illustrated The present trolling device is highly effective in accomplishing the desired trolling results. It will function with propellers 44 of different over-all diameters, it being but necessary to vertically adjust the plate 14 from the position shown in Figures4 and 5 to function with propellers 44 of lesser diameter or disposed at a relatively higher elevation.

It is manifest that there has been provided a trolling device which fulfills the objects and advantages sought therefor.

It is to be understood that the foregoing description and the accompanying drawing have been given by way of illustration and example. It is also to be understood that changes in form of the elements, rearrangement of parts, and substitution of equivalent elements, which will be obvious to those skilled in the art, are contemplated as within the scope of the present invention which is limited only by the claims which follow.

What is claimed is:

1. A trolling device for reducing the effectiveness of a propeller comprising a flat mounting plate, and a at water diverter plate adjustably connected to said mounting plate in contiguous overlapping relation, said diverter plate and said mounting plate being in parallel planes, said diverter plate extending downwardly from said mounting plate when in water diverting relation, said diverter plate being slidably adjustable relative to said mounting plate for determining the amount of water diverted by the former.

2. A trolling device for reducing the effectiveness of a propeller comprising a flat mounting plate, and a flat water diverter plate adjustably connected to said mounting plate in contiguous overlapping relation, said diverter plate extending downwardly from said mounting plate when in water diverting relation, said diverter plate being slidably adjustable relative to said mouting plate for determining the amount of water diverted by the-former, said diverter plate being pivotally adjustable relative to said mounting plate to dispose the former in transverse relation to and above the lower edge of the latter for inoperative position of the former.

3. In combination with a boat including a transom and an outboard motor including a propeller and an adjacent gear casing mounted on said transom, a trolling device mounted upon said boat in cooperative relation with the outboard motor and propeller comprising a mounting plate for disposition between the boat transom and the outboard motor, said plate being of a length to depend a distance short of the bottom of the transom, and a diverter plate adjustably mounted on said mounting plate and depending therefrom into position forwardly of the propeller to divert water from the propeller, said diverter plate being adjacent to and in overlapping relation with said mounting plate for a substantial portion of each.

4. In combination with a boat including a transom and an outboard motor including a propeller and an adjacent gear casing mounted on said transom, a trolling device mounted upon said boat in cooperative relation with the outboard motor and propeller comprising a mounting plate for disposition between the boat transom and the outboard motor, said plate being of a length to depend a plate"being 'adjacent to and in overlapping'reltioii-'Witl'r and the outboard motor, said plate being of a length to depend a distance short of the bottom of the transom, and a diverter plate adjustablyl mounted on said mounting plate and depending therefrom into position forwardly of the propeller to divert water from the propeller, said diverter plate being adjacent to and in overlapping relation with said mounting plate for a substantial portion of each, sa-id adjustable mounting including resilient means permitting bodily movement of thediverter plate away from the mounting plate to permit movement of the former into engagement with the gear casing forwardly of the pro pellet'.

vReferences Cited in the le of this patent UNITED STATES PATENTS 1,576,237 Dawson Mar. 9, 1926 2,256,898 llhmke Sept. 23, 1941 2,265,625 Buck Dec. 9, 1941 2,288,504 Weber June 30, 1942 2,654,336 Katzung et al Oct. 6, 1953 

